We hypothesized that the presence of an abnormal ventricular mechanical activation sequence and/or a delayed left ventricular (LV) contraction may have adverse hemodynamic effects in congestive heart failure (CHF) and could be improved by synchronous RV-LV pacing in a multisite (MS) configuration. 8 NYHA IV CHF patients were included with a LV delay due to 1/ preexistent pacemaker in 4 pts (2 VVI and 2 DDD); 2/ left bundle branch block in 2 pts; 3/ intraventricular conduction delays in 2 pts. An acute hemodynamic evaluation was performed. Hemodynamics were optimized in standard RV pacing by modifying RV lead position from apex to outflow tract (RVOT) in VVI for AF patients and in VDD for sinus rhythm patients at different AV delays. RV pacing did not change hemodynamics whatever the lead position. BV pacing improved CI by 25% (p < 0.006), V wave by 26% (p < 0.004) and PCWP by 17% (p < 0.01). Chronic implantation was performed in 7pts. LV lead was implanted via the coronary sinus in 2 cases and epicardial via a thoracoscopic approach in the remaining ones. 1 pt died during LV lead implantation. Hemodynamics were tested at 2 months followup (FU). Switching BV pacing off was associated with immediate deterioration. At 6 +/- 6 months Followup 4 pts are stable in Class II. 1 pt died of cardiac cause. 1 pt could be transplanted at 17 months FU. In conclusion, BV pacing through a multisite configuration is feasible and can help in CHF patients managing.